In the field of graphic arts, a high contrast image-forming system is used to obtain good reproduction of continuous tone images comprising dot images or good reproduction of line images. For this purpose, a lith developer system has been heretofore employed.
In order to obtain the photographic characteristic of high contrast using stable developing solutions, a method has been developed and principally employed using hydrazine derivatives as described in U.S. Pat. Nos. 4,224,401; 4,168,977; 4,166,742; 4,311,781; 4,272,606; 4,211,857; and 4,243,739. This method provides high contrast and high sensitivity and allows sulfite to be added in high concentration to the developing solution so that the stability of the developing solution against air oxidation is greatly improved as compared to the lith developer. Also, the surfaces of photographic materials for use in photo-mechanical processes (the upper layer of photographic emulsion layers or the back layers) are matted to prevent the occurrence of uneven images due to the formation of Newton rings and to carry out uniform vacuum-enlarging in a short time when conducting camera work or print work. The thus matted surfaces do not adhere to one another when the photographic materials are stored. Finely-powdered inorganic water-insoluble compounds such as silica, alumina, barium sulfate, and calcium carbonate and finely-powdered organic compounds such as starch, polymethylmethacrylate, and polystyrene have been used as matting agents. Of these, polymer matting agents are preferable because the desired uniform grain size is easily obtained.
However, the use of polymer matting agents causes small black spots on the blackened edges of the images. The inventors have studied this phenomenon and have found that the areas of the photographic material containing the polymer matting agents have a higher value of optical transmission and are therefore fogged to result in black spots. Moreover, it has been found that the coexistence of the polymer matting agents and optical filter dyes brings about even more distinct black spots. Thus, the problem of black spots caused by light leakage needed to be solved.